Cap for armor-piercing projectiles.



R. A. HADFIELD. GAP FOR ARMOR PIERGING PROJEGTILES.

KPPLIGATION FILED AUG. 22, 1913.

Patented Mar. 10, 1914,

[12 yen for a '1 '0 att whom it may concern st rrup STATES ra'rnn'r orrron.

ROBERT ABBOTT HAIDF IELD, OF WESTMINSTER, ENGLAND.

CAP FOR ARMOB-PIERCING PROJEG'JJILES.

aosaeee,

Specification of Letters Patent.

Application filed August 22, 1913. Scrial No. $86,131.

Be it known that I, Sir ROBERT ABBo'i'r HADFIELD, knight, F. R, S.. a subject of the King of Great Britain and Ireland, residing at Westminster, England, have invented Improvements in Caps for Armor-Piercing Projectiles, of which the following is a specification.

In caps "for armor-piercing projectiles as heretofore employed, it has been usual to make that portion'of the cap that surrounds the pointed end portion of the projectile of comparatively large cross sectional area in a plane transverse to the axis of the cap and projectile at the point of the-latter, the front end of the cap, which is sometimes made comparatively thin immediately over the point of t projectile, being usually made flat, or conve with a large radius of curvature, or of hollow or cup shape, or of conical shape, the object being to provide a mass of metal that will strike the armor plate to be pierced, over a comparatively large area, and to provide a large mass of metal around the pointed end of the projectile for'supporting the same immediately before and just after-the projectile reaches the plate, a When, however, a projectile fitted with such a cap strikes an armor, plate, either normally or obliquely, the cap is liable to be shifted in position relatively to the projectile before the critical moment when the point of the projectile comes in contact'with the plate with the result that the projectile is liable to be ineffective.

Now, instead of its being necessary to protect the extreme point-of the projectile with .such extreme care/as hasheretofore'been ,"usually considered des rable, I have found that while itis desirable to protect the-point of the projectile by a thin layer of cap metal arranged to come between it and the face of I the plate to be perforated, as heretofore, yet the'further massing of such metal around the extreme point is unnecessary. In order that the projectile shall derive the maximumsupport from the cap it is of importance that the work of expanding or laterally'displacing the cap metal should not commence substantially before the critical moment whenv the point of the projectile meets the face of :the plate. With this object in view I'have found that the metal of the cap arranged immediately infront of the extreme point of the projectile should be so disposed that it; ormost of it,' can be displaced and got rid of or perforated without seriously disturbing the firm setting of the cap on the ogival portion of the projectile or causing it to moyerelatively to the projectile itself. With exist ngcaps this firmness or solidity of setting is liable to be disturbed and the cap metal to be displaced before the criticalmoment 1n question. -In the event of such.

premature disturbance, although a fair 'result maybe obtained, it often ha pens that the. projectile either does not get t rough the.

plate at all, or only a portion gets through, owing to itsnot receiving the maximum support from the cap.

Now the present inventien has her object to provide caps designed to enable projectiles to perforate hard faced armor in a reliable and effective manner under varying service conditions. To this end, a cap ac-' cording to the present invention is construct-' ed so that its forward face presents a centrally-arranged portion of comparatively small thickness and cross sectional area to fit over and cover the pointed end of the projectile and with a hollow rea'rWa'rdly-ex-' tending body portion to fit over and sur- Patented Mar.10,191&.

round the ogival portion of the projectile, I

such body portion having its forward end located behind or below a plane transverse to the axis of the cap and projectile and passing through the point of the latter. The distance that this forward end is located behind the point of the projectile may vary from 'say one-fiftieth of the caliber ofthe shell to onetenth of the caliber of the shell,

or any intermediate measurements. The

surface of the centrally-arranged forward portion of the'cap merges into that of the forward end of the body portion of the cap through an intermediate annular surface of concave .or other curved or irregular shape other than a straight shape as seen in a lon- 'gitudinal section of the cap 'so that the front end of the cap is not of conical shape extending gradually backward beyond the front of'the projectile but after passing over the, front of the projectile, turns outward to form the front end of the rear or body portion of the cap. With such a construction it will be understood that a line drawn as a tangent to thewcentrally-arranged forward portion and to the body portion of the cap will touch these portions at two points and bridge the intermediate surface of the cap. The central forward portion of the cap is preferably made with a convex surface of comparatively small radius of curvature and very slightly in front of the point of the projectile, or'in some cases it may not be appreciably in front of the extreme point of the projectile at all, and with an annular connecting surface between the said central forward portion and the body portion so therewith.

. In the accompanying drawings, Figure 1 shows partly in, elevation and partly in central vertical section and by way of example only, a portion of an armor piercing projectile haying a head of say two calibersradius fitted with a cap constructed according to the present invention. Fig. 2 is a similar view to Fig. 1 showing a modified construction.

Referring to Fig. 1, a is the comparatively thin centrally arranged forward portion of the cap made of a small diameter a: and with a convex surface of small radius, and b isthe hollow rearwardly extending body portion of the cap madeof comparatively small cross sectional area' and with a rounded shoulder at 6 the front surface of the twoportions a and I) being merged or connected together an intermediate annular surface 0 shown as of step-like shape in section, that lies substantially behind the point of the projectile f. It will be seen that the forwardend 6 of the body portion b of the cap is located well behind a transverse plane A A passing through the point of the-pro jectile and that the intermediate portion of the cap bounded by the surface 0 is bridged by a line B B tangent to the central forward and bodyportions a and Z) of the .cap

and touching the same at the points X and Y.

In Fig. 2 the intermediate surface 0 is of concave shape and the forward end of the body portion 1) extends forward to a greater extent than in Fig. l, and has a hollowair deflector, mantle or shield g of known construction secured thereto to facilitate flight of the projectile as well understood.

Upon impact of a projectile fitted with a cap such as hereinbefore described against a. hard-faced armor plate the force of the impact will, owing to the small surface area of the central forward portion a of the cap,

be concentrated over a small surface'area of the armor and the said central portion will be compressed, perforated, or turned out of the way, by the point of the projectile f, without seriously disturbing the jectile, so that it can offer effective protcction to the rojectile atthe moment required, name y when the point of the jectile reaches the armor.

Vhat I claim. is

1. A pointed armor piercing projectile and a cap for the forward, portion thereof, said cap comprisin a relatively thin central portion, formed of small radius of curvature to cover the projectile tip and a relatively thick body extending rearwardly therefrom, the forward end of the body being behind the projectile tip, and the forward surface of the cap bein formed with an annular concavity rearwardly of the tip and around said relatively thin, central portion, leaving the tip covered and surrounded only with a relatively thin covering, giving a small point of contact, but a greater thickness of metal in the body and a firm support to the projectile after the tip, has penetrated.

2. For an armor piercing projectile, a cap having a centrally arranged forward por-' tion of a small axial thickness to fit over'the point of a projectile and a hollow rear or body portion to fit'over the ogival portion of the projectile, the front end surface of the body portion having an annular depression therein and joining the outer peripheral surface of the body portion behind a plane transverse to the axis of the projectile and passing through the point of the projectile,

the greatest transverse thickness of the cap metal being around the pointed end portion of the projectile but behind the actual point of the projectile, substantially as described.

8. For an armor piercing projectile, a cap having a concave-convex front end surface, the convex surface being centrally arranged and the concave surface extending around the central portion and terminating in a substantially plane annular outer portion located behind the point of the projectile to which the cap is fitted.

4. For an armor piercing projectile, a cap having a centrally arranged forward portion of small axialthickness and cross'sectional area to fit over the pointed end portion of a projectile and a hollow rear or body portion to fit over and surround the ogival portion of the projectile. the body portion having its front end surface arranged to come well behind av plane transverse to the axis of the cap and passing through the point of the projectile and the surfaces of the said forward portion -and front end of he body portion being joined by an interbody portion b or causing it to commence projectile comprising a'relatively thin cento expand or move relatively to the prol l l prowith a convex surface a relatively thicker body extending rearof the cup increasing-and its thickness dewardly therefrom the forward end of the creasing toward the rear. 10

'bodybeing behind the projectile tip, and Signed at London, Englandgthis sixth .the forward surface being a single continuday of August, 1913.

ous curved surface, the outer edge thereof ROBERT ABBOTT HADFIELD. being behind the projectile t-ip, and from Witnesses: I said outer edge the body extends rearwardly "ARTHUR WOOSNAM, g

in a rounded shoulder, the total diameter CHARLES VIVIAN GURNEY.

copies of this patent may he obtained tor five cents each, by addressing the Gommlnioner of Patents. v Washington, D. 0.. 

